Author Topic: 0-5V reference  (Read 16310 times)

Bill

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0-5V reference
« on: April 15, 2005, 02:15:47 PM »
First, thanks for a great product!  I use your T100MD1616+  for all of my OEM products.

I have found that when installed correctly, this PLC functions flawlessly.  I have one operating a communications system that has been functioning without incident for almost 2 years!

Now to my question.  I would like to use a 0-5V reference voltage to control low speed cutoff for a valve
that applies a coating to a surface at high speeds.  I have already used both high speed counter inputs for other measurement purposes leaving no available high speed inputs for frequency measurement.  Can I use the analog input to measure 0-4096 based on input voltage to turn the valve off at some predefined voltage level, or should I consider another method to achieve the desired result?  My project is on a very tight budget.

Thanks again for a versatile controller and great tech support.

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Re:0-5V reference
« Reply #1 on: April 15, 2005, 03:40:40 PM »
Thank you for your kind comments. We are happy to learn that the T100MD+ PLC works out well for your projects.

You certainly can use the analog input to measure a sensor output provided the sensor output voltage or current that falls in the range of the ADC inputs. E.g. for T100MD1616+ there are two channels of 0-1V analog inputs and two channels of 0-5V analog inputs.  If your sensor output 4-20mA current you can still convert it to 1-5V using the a 250 Ohm resistor.  Based on the input reading (0-4096) you can scale it to whatever reference value you desire using formula described in the "Frequently Asked Questions" board in this forum, as follow:

http://www.tri-plc.com/yabbse/index.php?board=2;action=display;threadid=349

You can then compare the scaled readings to the desired set values and decide to turn ON/OFF the valve. You can also use the PWM output to control variable opening for a proportional type valve (i.e. not ON/OFF only type).
Email: support@triplc.com
Tel: 1-877-TRI-PLCS

Bill

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Re:0-5V reference
« Reply #2 on: April 15, 2005, 09:21:17 PM »
Thank you.